Officers were called to the north bank of the river, west of Plano Street Bridge, on Wednesday after receiving reports of an unresponsive man on the ground.
When investigators arrived, they found the victim dead with "significant injuries to his face," police say.
Porterville police have identified the victim as 46-year-old Tongtaem Ratsakhy.
Police are calling Ratsakhy's death suspicious. Investigators have not released his official cause of death.
Detectives processed the scene for evidence and spoke with potential witnesses.
Authorities are asking anyone with information on the case to call the Porterville Police Department at 559-782-7400.